Electroblotting is a widely used biotechnology technique that involves applying a potential difference across a matrix in which charged analytes, such as DNA, RNA, or protein, are distributed. The potential difference causes the analytes to migrate out of the matrix and become deposited on a surface, or “blot”, next to the matrix, where they are immobilized. The analytes can then be detected using fluorescence, chemiluminescence, radioactivity, or other phenomena, by probing the analytes with one or more detectable binding partners.
Various kinds of electroblotting are known and practiced in the art. When the analytes are DNA fragments, the transfer of the analytes out of a gel or other matrix and onto a blot is called Southern blotting after its originator, the British biologist Edwin M. Southern. By analogy, the transfer of RNA fragments is termed northern blotting, and the transfer of proteins or polypeptides is termed western blotting.
Fluorescence detection is a useful method for western blotting and other electroblotting applications. Proteins immobilized on a surface of a western blotting membrane are commonly labeled with fluorescent markers for specific antibody detection. The fluorescent markers can be excited from above by an excitation source, with the fluorescent markers emitting light at a slightly longer wavelength, which is detected by an imaging system.